Monday, August 27, 2007

GSI Data Update For Telescope Shiners

We now have 7 months' worth of gonadosomatic index (GSI) data for telescope shiners out of Hurricane Creek at the Walls of Jericho. The data for both males and females (below) clearly show June as the peak spawning month, with everything completely wrapped up by August. I'm impressed that we find the exact same pattern for both males and females, with slower rises to a sudden spike in June followed by fall-off. The telescope shiner breeding season was certainly over by the end of July. We'll be going back to the Walls on Sept. 8 which should pretty much close the book on the warm season. We might try to find some young fish too, just to see what they look like.

Meanwhile, Jennifer is re-running ELISAs on five scarlet shiners' blood plasma for 11-ketotesterone today. She should get the results tomorrow morning after washing off the plates and scanning the resulting color. The five fish in question are those whose initial ELISA results were very high, which is believable, but they were at the very top of the standard concentration curve. Instead of running samples at a dilution of 1:100, we're running them at 1:1000 and 1:10,000. In life these fish were completely jacked up on 11-KT. If this goes well, that should wrap up Jennifer's ELISA work and she can move on to analyzing digital images of these fish for intensity of body and fin color.
Remember, if you click on the graphs above, they'll appear larger in a new window.

Friday, August 24, 2007

The Verdict Is In: Female Telescope Shiners Are Bigger Than Males

It's a relationship that only a fish geek can love (or appreciate?). With the data I have to date from our monthly collections of telescope shiners since February, the females are longer than the males, 50.5 mm average length for females (117 individuals) vs. 45.3 mm for the males (140 individuals). Comparing the two data sets with a t-test shows that they are statistically significantly different with a p<<.001, i.e. a decisive value. This is interesting in of itself, but it's different from the telescopes' near relative, the silverstripe shiner, in which I found that on average females are slightly longer but not significantly so. One advantage to larger body size for a female fish would be the ability to produce more eggs. I don't know if that's what drives this relationship here, though, since we haven't explicitly looked for the relevant factors.

In other news, thanks to everyone who has mentioned the Discovering Alabama episode. The one thing people have remarked on is that I never wear a lab coat and they find it funny that I'm wearing one in the episode. Even worse, that lab coat doesn't fit but luckily it's not obvious. Maybe I should go out and get a nice size 50 long lab coat that's stylishly cut? We'll see....

Sunday, August 19, 2007

Discovering Alabama Episode

Ruth and I went to the local premiere of the new "Discovering Alabama" episode for Alabama Public Television (APT) Thursday evening. This episode is about threats to the Flint River here in Madison County, Alabama. The presentation is more pointed than typical episodes in the series. Rather than a general feeling of, "everything is really beautiful in this beautiful state", very stark problems and issues of suburban development and environmental degradation are examined. Some of the interviews with me in the episode push this forward, but others who speak in the episode have similar things to say. I had forgotten that I mention "dog poop" as part of non-point source pollution, but there it is in the episode(!). I also get to mention flame chubs and threats they face through habitat loss. The film crew even visited and filmed a local spring I told them about that's the site of a local property owners' association working very hard and stupidly to kill off this spring which is loaded with the most beautiful flame chubs we found.

I can only imagine that many developers and their hangers-on won't be favorably impressed by this episode. But that's a good sign. Like the man said, money doesn't talk, it swears.

The broadcast premiere is Tuesday night at 8 on your local APT station (channel 25 in Huntsville).

Wednesday, August 15, 2007

A Last Push On Scarlet Shiner Brains

I went out this afternoon with Enrique and Rebecca to catch a final 10 scarlet shiners. We needed fresh brains of nonreproductive females, which at this time of year is most of them. Enrique and Rebecca are running a last round of Western blots to determine NMDA receptor concentrations in the three major brain areas. They're also running the same brain parts from male and female telescope shiners for comparison. The telescopes have a low level of sexual dimorphism while the scarlets have pronounced sexual dimorphism. Our hypothesis is that the telescope shiners should show less of a difference between males and females, that is, the two sexes should have similar levels of NMDA receptors. It would also be fun to check out 11-ketotestosterone levels in the telescopes, but we'll have to let that slide for now. If this works, Enrique's thesis work is finished and all he has to do is write it up and defend.

I gotta say you know we're tough, the temperature this afternoon was 39 deg. C, or 103 F. We all sweated, but that's what you have to do for real biology.

Monday, August 13, 2007

Just Thinking In The Heat

Preliminary observations of the telescope shiners we collected last Tuesday show that their gonadal tissues are much reduced compared even to July. When Loren showed me the first ovary she dissected out, I thought it was a testes; nope, they're really that reduced. And the testes are out-and-out difficult to find now. So I'm sure that the GSI values for August will be way down. But this is what happened with burrhead and silverstripe shiners from Borden Creek three years ago, so it's not really a surprise. We also collected the smallest telescope we've found yet, at 27 mm. Our seine is relatively coarse so there has been size selectivity all along. But now with that individual I think we caught a subadult who was born in 2006. One expansion of our current research would be to look for young of the year (YOY) fish and observe their growth rate. At the least, I think we'll try to catch some in September and see what we find. This assumes that I'm confident of species ID on 15 mm fish, or whatever exact size they are. We'll see...

Tuesday, August 07, 2007

An Easy Trip In & Out Of The Walls Of Jericho

This month's trip to the Walls of Jericho to collect telescope shiners went well. The whole state is under a heat advisory but hanging out in a fairly shady creek wasn't so bad. We caught 40 telescopes in not even 45 minutes because the creek was so low. This means that we didn't have to run around as much as we usually do, good on a day when it was about 97 deg. F.

Below is a picture of one of the many frogs hanging out in the streambed rocks that are usually covered by water. He held still just long enough on Loren's hand for me to turn on the macro-focus feature on my camera, steady my hands for the shot, and make the shot.

In the photo below my seining team looks like they're on a scavenger hunt. Most of this area is under calf-deep water most of the year. I think the big draw was to find interesting rocks, although the realization was dawning that the area was also full of frogs and spiders.

This was Jennifer's first trip to Hurricane Creek with us. She's also driven in with a bird netting team from Alabama A&M. I was honored, she said that riding in my (hotrod) Toyota truck was smoother than the Ford F-150 A&M truck. Partially I think it's because I've learned how to drive the road, with all of its protruding sandstone and oddly placed mudholes.

Friday, August 03, 2007

We Have 11-KT Data For Scarlet Shiners

I said last time that I would tell you, and I will -- Jennifer's ELISA run for scarlet shiner 11-keto-testosterone levels yesterday worked. She ran the test on blood plasma samples from 20 fish: 7 alpha males, 7 sub-alpha males, and 6 females. From what I could see the ELISA showed sky-high 11-KT levels in the alpha males, somewhat lower levels in the sub-alpha males, and very low levels in the females (like maybe 1% the level of alpha males). So this is exciting, it's real science!

I counted and measured the eggs in 5 telescope shiner ovaries from February yesterday. Not surprisingly these ovaries are small and not very well developed. One of the ovaries only had 2 eggs in it, so I'm dropping it from the analysis. The other four were the largest out of about a dozen females in that collection. These four ovaries averaged 98 developing eggs in an early stage of maturation (early exogenous vitellogenesis), and a mean egg size of 0.65 mm (650 micrometers). For mean size I measured 5 eggs from each individual, which seems to be enough to give a good picture. By comparison, some of the June ovaries have at least 600 eggs and a mean egg size of 1.4 mm from quick examination. Doing this work from a digital image is much easier than looking through a microscope, so I approve of this method. On to more data.......

Wednesday, August 01, 2007

Everything's In Motion, In A Good Way

Jennifer started her ELISA run for scarlet shiner 11-ketotestosterone (11-KT) this afternoon. This is a big run, setting up more than 170 small tubes to incubate overnight. She's running triplicates of a bunch of shiner blood samples, male and female, and also standards of 11-KT and both positive and negative controls. By 10 tomorrow morning they'll be ready to be scanned and read in a spectrophotometer to determine concentrations of 11-KT. If it works, much of her thesis research is done; I don't want to think about what happens if it doesn't. One would assume that the males will have higher 11-KT levels than the females. I'll tell you what happens.

We started to count and measure telescope shiner eggs today on the other big project. We've photographed all of the ovaries we have from February on. Only 5 of the February ovaries were large enough to be worth photographing the same way we've done with ovaries from later in the season. The first three ovaries to be counted and measured were all from March. All of the oocytes were at a fairly early stage of development I would describe as early exogenous vitellogenesis. The egg counts ranged from 229 to 446 per fish. Measurements of the diameters of five random eggs from each fish were pretty tightly clustered at 0.7 mm. It's tedious work but yields interesting data (I kept telling that to Stephanie and Nicole who did the counts and measurements).

I heard from Nick Sharp today, who started his new job in Montgomery. He says that he drove the road into the Walls of Jericho last week and it was all clear. Hopefully that will be the status next Tuesday for our next trip.